When importance is placed on very homogeneous mixtures of highly viscous fluids of two or more components, whereby at least one of said components is highly viscous, mixing and conveying is usually done in separate devices. A particular disadvantage of the devices is that both devices must be changed over and cleaned, which is time consuming during a change-over from one component to another component, which results in a substantial amount of work during the processing of highly viscous fluids, especially in the plastics industry.
Combination mixing and conveying devices for highly viscous fluids of the above mentioned type are already known. For example German OS No. 33 13 710 describes an agitation device with which both a mixing and also a conveying action can be achieved. The mixing and conveying device consists substantially of a cylindrical housing, on an inner wall of which there are mounted several stationary guide blades, forming guide wheels, and relative to which extends coaxially a rotor shaft with rotors, so that the cylindrical housing with the guide blades forming guide wheels and being stationary on its inner wall forms the stator and the rotor shaft with the rotors arranged thereon forms the rotor. It furthermore has a slide-ring packing which seals off a mixing chamber to the outside and has lateral inlet openings for entry of the fluids to be mixed and an outlet opening for the ready mixture.
It is true that it is possible with this agitation device to substantially increase the mixing and conveying action, in particular for operations in the fiber technology or for example during the manufacture of photo-emulsions. However, the manufacture of the stationary guide blades forming guide wheels in the shape of prongs, complicated in their form, for the stator and also the manufacture of the guide wheels for the rotor, which guide wheels also consist of prongs and are arranged on the rotor shaft, is very complicated and accordingly expensive. Since the agitation device is similar in characteristic to a spiral conveyor, it has, because of the intensive mixing action which is to be achieved, also a structural length which is still too long and is therefore also expensive to manufacture. Also if mixing and conveying takes place in separate agitation devices, a change-over and a time-consuming cleaning of the devices is needed for changing from one component to another component. This results during the processing of highly viscous fluids, particularly in the plastics industry, in a considerable amount of work. An admixing of one or several components during the mixing or conveying is also not possible.
German AS No. 1 150 360 discloses a kneading and fine-grinding machine for pastelike masses, in particular for tough or initially very coarse pastelike masses, like chocolate masses, color bases and other chemical and pharmaceutical products. The kneading and fine-grinding machine has a double-cylinder trough arranged in a lying position and two shafts which are rotatably supported in its cylinder axes, rotate at the same speed and are provided with inclined positioned kneading and fine-grinding members reaching to the inner surfaces of the cylinder. The distance between the shafts is less than the diameter of the circles described by the outer edges of the kneading and fine-grinding members. The kneading and fine-grinding members of the machine are constructed in a conventional manner as circular-sector-shaped, preferably flat vanes which are arranged in rows and are provided with openings. The vanes of the one kneading shaft are thereby positioned oppositely inclined to the ones of the other kneading shaft.
The two shafts are coupled automatically with one another so that they can be driven in the same direction of rotation and at the same speed and that the rows of vanes of the two shafts comb through one another in the center of the trough. Sector angle and the inclined position of the vanes and their reciprocal distance are chosen such that during one rotation of the shafts, the inner surfaces of the cylinder are completely brushed over by the outer edges of the vanes and that only a small clearance distance remains between the side edges of the vanes, which side edges pass one another when the rows of vanes comb through one another.
This kneading and fine-grinding machine can achieve a particularly strong kneading and grinding action, for example for tough or initially very coarse pastelike masses, like chocolate masses, dyes and other chemical and pharmaceutical products. Yet this kneading and fine-grinding machine is not suited as a mixing and conveying device for highly viscous fluids. One or several components of the masses in consideration here also cannot be admixed additionally.
French Patent No. 15 23 920 describes a device for mixing of two fluids or gases for the manufacture of fuels. The components of the fluids r gases are each supplied separately through a pipe and a supply line. The pipe is connected to a housing through a connection and is arranged perpendicularly to the housing and supplies the fluids or gases at a high pressure to the housing. The supply line, which extends coaxially to the housing and is flangedly connected to the housing, supplies the fluids or gases at a low pressure to the housing. After the mixing operation is over, the fluids or gases are discharged through an outlet pipe also connected by a flange to the housing. A feed pipe coaxially arranged in the housing and secured by flanges has several openings in its periphery which are connected with an annular chamber created by the pipe line. An inner central pipe mounted on the pipe line and extending in longitudinal direction of the housing has a row of openings provided on the periphery from which the fluid or the gas, after being supplied through an elbow and finally through a hemispherical wall of the inner pipe, can flow into a passageway. Due to the fact that the individual components of the fluids or gases to be mixed can be supplied under different pressures, the necessary movement of the components for their thorough mixing is produced.
Thus the description of this device clearly shows that it is easily suited for the manufacture of homogeneous mixtures from two fluids or gases, however, that it cannot at all be used for the combined mixing and conveying of highly viscous fluids because of its design. The supply line mounted perpendicularly with respect to the housing also is not a mixing nozzle.
Therefore, the basic purpose of the invention is to provide a combination mixing and conveying device for highly viscous fluids, whereby the mixing and conveying device is constructed as a single or multi-stage axial centrifugal pump, in which the highly viscous fluids to be mixed can be supplied laterally and in which the mixing and conveying members are arranged such that an upper housing part with important parts of the device can be lifted off from a lower housing part, so that a changing from one component to another component is possible without a change-over and expensive cleaning of the device.
The advantages achieved with the invention consist substantially in a change-over of devices and their time-consuming cleaning no longer being needed during a changing from one component to another component of highly viscous fluids to be mixed and conveyed, because the combination mixing and conveying device is constructed as a single or multi-stage axial centrifugal pump in which the mixing and conveying members are arranged such that an upper housing part with important parts of the device, after a releasing of screws, can easily be lifted off from the lower housing part. This substantially simplifies the servicing and cleaning of the mixing and conveying device. The individual components are inventively supplied through a lateral adapter piece prior to their being able to supply the first rotor. The mixing of the respective, partially highly viscous fluids takes place only in the pump itself, whereby a gasket mounted in an annular groove prevents the penetration of fluids into the upper housing part, so that the support of the rotor shaft cannot be damaged. Due to the fact that at least one mixing nozzle is provided in the lateral adapter piece, a second component of a highly viscous fluid can be supplied during the mixing. Several holes in the mixing nozzle assure in an advantageous manner a better pre-distribution of the second component. For a better vorticity of the mixture in the axial centrifugal pump, the rotor blades of the guide wheels in particular are provided in a conventional manner with at least one hole.